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From: Keith Busch <keith.busch@intel.com>
To: Sinan Kaya <okaya@codeaurora.org>
Cc: linux-nvme@lists.infradead.org, timur@codeaurora.org,
	linux-arm-msm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, Jens Axboe <axboe@fb.com>,
	Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] nvme: Acknowledge completion queue on each iteration
Date: Mon, 17 Jul 2017 18:45:51 -0400	[thread overview]
Message-ID: <20170717224551.GA1496@localhost.localdomain> (raw)
In-Reply-To: <1500330983-27501-1-git-send-email-okaya@codeaurora.org>

On Mon, Jul 17, 2017 at 06:36:23PM -0400, Sinan Kaya wrote:
> Code is moving the completion queue doorbell after processing all completed
> events and sending callbacks to the block layer on each iteration.
> 
> This is causing a performance drop when a lot of jobs are queued towards
> the HW. Move the completion queue doorbell on each loop instead and allow new
> jobs to be queued by the HW.

That doesn't make sense. Aggregating doorbell writes should be much more
efficient for high depth workloads.

WARNING: multiple messages have this Message-ID (diff)
From: keith.busch@intel.com (Keith Busch)
Subject: [PATCH] nvme: Acknowledge completion queue on each iteration
Date: Mon, 17 Jul 2017 18:45:51 -0400	[thread overview]
Message-ID: <20170717224551.GA1496@localhost.localdomain> (raw)
In-Reply-To: <1500330983-27501-1-git-send-email-okaya@codeaurora.org>

On Mon, Jul 17, 2017@06:36:23PM -0400, Sinan Kaya wrote:
> Code is moving the completion queue doorbell after processing all completed
> events and sending callbacks to the block layer on each iteration.
> 
> This is causing a performance drop when a lot of jobs are queued towards
> the HW. Move the completion queue doorbell on each loop instead and allow new
> jobs to be queued by the HW.

That doesn't make sense. Aggregating doorbell writes should be much more
efficient for high depth workloads.

WARNING: multiple messages have this Message-ID (diff)
From: keith.busch@intel.com (Keith Busch)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] nvme: Acknowledge completion queue on each iteration
Date: Mon, 17 Jul 2017 18:45:51 -0400	[thread overview]
Message-ID: <20170717224551.GA1496@localhost.localdomain> (raw)
In-Reply-To: <1500330983-27501-1-git-send-email-okaya@codeaurora.org>

On Mon, Jul 17, 2017 at 06:36:23PM -0400, Sinan Kaya wrote:
> Code is moving the completion queue doorbell after processing all completed
> events and sending callbacks to the block layer on each iteration.
> 
> This is causing a performance drop when a lot of jobs are queued towards
> the HW. Move the completion queue doorbell on each loop instead and allow new
> jobs to be queued by the HW.

That doesn't make sense. Aggregating doorbell writes should be much more
efficient for high depth workloads.

  reply	other threads:[~2017-07-17 22:39 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-07-17 22:36 [PATCH] nvme: Acknowledge completion queue on each iteration Sinan Kaya
2017-07-17 22:36 ` Sinan Kaya
2017-07-17 22:36 ` Sinan Kaya
2017-07-17 22:45 ` Keith Busch [this message]
2017-07-17 22:45   ` Keith Busch
2017-07-17 22:45   ` Keith Busch
2017-07-17 22:46   ` Sinan Kaya
2017-07-17 22:46     ` Sinan Kaya
2017-07-17 22:46     ` Sinan Kaya
2017-07-17 22:56     ` Keith Busch
2017-07-17 22:56       ` Keith Busch
2017-07-17 22:56       ` Keith Busch
2017-07-17 23:07       ` okaya
2017-07-17 23:07         ` okaya at codeaurora.org
2017-07-17 23:07         ` okaya
2017-07-18 14:36         ` Keith Busch
2017-07-18 14:36           ` Keith Busch
2017-07-18 14:36           ` Keith Busch
2017-07-18 18:52           ` Sinan Kaya
2017-07-18 18:52             ` Sinan Kaya
2017-07-18 18:52             ` Sinan Kaya
2017-07-18 21:26             ` Keith Busch
2017-07-18 21:26               ` Keith Busch
2017-07-18 21:26               ` Keith Busch
2017-07-19  9:20 ` Sagi Grimberg
2017-07-19  9:20   ` Sagi Grimberg
2017-07-19  9:20   ` Sagi Grimberg
2017-07-19 10:37   ` Sinan Kaya
2017-07-19 10:37     ` Sinan Kaya
2017-07-19 10:37     ` Sinan Kaya

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